Occurrence and fate of 27 triazines and metabolites within French drinking water treatment plants

Twenty-seven triazines and metabolites were screened throughout six advanced drinking water treatment plants (DWTP) in France and their respective resources. Seven molecules were quantified in raw waters with a maximum concentration of 91 ng/L reached for desethyl-atrazine. No metabolites generated through advanced degradation pathways were quantified. Concentration profiles for five DWTP treating ground or surface waters were very similar and remained stable over time. Only one DWTP treating groundwater presented differences between sampling periods due to variations in wells operations. As expected, most treatment units (settling, ozonation, nitrification, sand filtration, chlorination) did not allow for efficient removal of these micropollutants. Adsorption on granular or powdered activated carbon (PAC) was highlighted as the best available technology for the majority of quantified compounds. Combined PAC and ultrafiltration treatment was especially adapted for the removal of hydroxy-atrazine, one of the most refractory components evaluated during this study. Indeed, among quantified pesticides, only hydroxy-atrazine and desethyl-deisopropyl-atrazine were measured in treated water, with concentrations below 12 ng/L.